198 Topics in Current Chemistry Editorial Board: A. de Meijere KN ...

Crystalline Polymorphism of Organic Compounds 197
D
C
B
A
NO 2 –N= NH
400 350 300 250 200 150 100 50
Fig. 14. 15 N CPMAS spectra for four polymorphs of the imidazole derivative 3. (Reprinted with
permission from [150], copyright 1996, Gordon and Breach Publishers)
differences were used to characterise conformations and crystal packing differences
in the three forms. Examples of applications of CPMAS to the study of
polymorphism and pseudopolymorphism of pure drug substances [27] as well
as drug-excipient mixtures [152] have been described.
In a recent study of the molecular motion in the crystal of the salt (4), the
results of 13 C CPMAS NMR and high-resolution powder XRD were combined
3 imidazole derivative 4 salt
PPM